This invention relates to a lightweight non-metallic extendable and retractable telescoping pole.
Retractable poles and masts have been fabricated mostly from aluminum, with a few devices made of fiberglass. Such prior designs typically weigh several hundred pounds and may use complicated networks of cranks or screws, lines or cables, and pulleys to extend or collapse the poles, resulting in a time-consuming operation each time the apparatus is to be extended or retracted.
For example, Goodman U.S. Pat. No. 3,296,757 discloses a telescoping mast apparatus wherein the mast is raised and lowered using a lead screw associated with a cranking mechanism. When the mast is first raised, the lead screw is detachably fastened first to the upper end of the topmost mast member. A crank and a set of bevel gears then raises the lead screw to thus raise and lower the topmost antenna mast member. When this portion has been raised, a pin is placed through an aperture in the bottom of this member and a corresponding aperture in the top of the next mast member. The lead screw is then detached from the topmost mast member and attached to the next mast member which is then raised in like manner by the crank and bevel gears. This process must be repeated to lift each mast member or section; and the process is then repeated in reverse to lower the antenna mast.
Roberts et al. U.S. Pat. No. 4,932,176 describes a telescoping mast system using wire ropes and pulleys mounted near or within tube collars so that the ropes and pulleys are totally enclosed within the mast system. The wire ropes are attached to a winch so that when the winch is rotated in one direction the ropes axially move the inner tubes from a nested or stowed position to a fully vertically extended position. When the winch is rotated in the opposite direction, the ropes apply a positive retracting force to the inner tubes to return them to a nested position.
It has also been proposed to use pneumatic pressure to extend an antenna mast formed of telescoping light metal sections. Rupprecht U.S. Pat. No. 4,137,535 discloses such a telescoping antenna mast wherein each section, except the bottom section, is provided with a piston attached to its lower end which fits into the next larger cylindrical section below the piston. Each piston has a passage for a gas to flow under pressure to the next section, commencing at the base or lowest section. The top section is closed at its upper end. The antenna mast is retracted by venting the bottom section whereby gas from the upper sections flow back through the passages in the respective pistons to thereby permit the mast to retract in a damped manner by its own weight.
However, while such a dampening mechanism may protect such a device from damage during retraction of the pole, it necessarily must not only reduce the speed of retraction, but the speed of extension as well. Furthermore, retraction of such a pole by its own weight obviously necessitates the use of a pole with sufficient mass to accomplish such retraction in an efficient manner. Therefore, there remains a need for a lightweight extendable and retractable pole which, while lightweight, may be both quickly extended and retracted.